The hypothesis that the S allele of the 5-HTTLPR serotonin transporter promoter region is associated with increased risk of depression, but only in individuals exposed to stressful situations, has generated much interest, research, and controversy since first proposed in 2003. Multiple meta-analyses combining results from heterogeneous analyses have not settled the issue. To determine the magnitude of the interaction and the conditions under which it might be observed, we performed new analyses on 31 datasets containing 38 802 European-ancestry subjects genotyped for 5-HTTLPR and assessed for depression and childhood maltreatment or other stressful life events, and meta-analyzed the results. Analyses targeted two stressors (narrow, broad) and two depression outcomes (current, lifetime). All groups that published on this topic prior to the initiation of our study and met the assessment and sample size criteria were invited to participate. Additional groups, identified by consortium members or self-identified in response to our protocol (published prior to the start of analysis1) with qualifying unpublished data were also invited to participate. A uniform data analysis script implementing the protocol was executed by each of the consortium members. Our findings do not support the interaction hypothesis. We found no subgroups or variable definitions for which an interaction between stress and 5-HTTLPR genotype was statistically significant. In contrast, our findings for the main effects of life stressors (strong risk factor) and 5-HTTLPR genotype (no impact on risk) are strikingly consistent across our contributing studies, the original study reporting the interaction, and subsequent meta-analyses. Our conclusion is that if an interaction exists in which the S allele of 5-HTTLPR increases risk of depression only in stressed individuals, then it is not broadly generalizable, but must be of modest effect size and only observable in limited situations.

Despite a social structure where elderly persons often live with their children and social interaction is likely to be more family-centered than in western countries, data from Taiwan suggest that participation in social activities outside the family may have a bigger impact on cognitive function than social contacts with family or non-relatives.

We provide a simple and straightforward method for estimating the proportion of deaths attributable to smoking in high-income countries. Our results demonstrate that smoking has played a central role in levels, trends and international differences in mortality over the past half century.

The theory of allostatic load describes how the cumulative experience of emotional challenges and stressful events over the life course may take a significant physiological toll on multiple interrelated systems of the body. Various summary measures of these effects have been proposed in the literature, but few studies focus on systematically evaluating them. We use data from a population-based sample of older Taiwanese to compare the explanatory power and cross-sectional predictive performance of several measures of allostatic load for diverse health outcomes. We find that choices regarding which biomarkers to include in a summary measure and how the measure is formed have modest effects across the basic prediction models we evaluate. Our findings suggest that count-based summary measures incorporating risk at both high and low tails and measures that preserve the continuous properties of the biological variables are strategies that may yield stronger predictions of a wider array of health outcomes than other measures. These fundamental insights are useful for researchers in search of empirical formulations of allostatic load and for those who are focused on the development of improved measurement strategies.

Long-term contraceptive use pattern is a valid predictor of unintended pregnancy risk. Policies aimed at reducing unintended pregnancies should target women who do not practice contraception and those who are sporadic users. Women in unstable relationships, those having infrequent sex and women who experience sexual coercion need access to methods, such as emergency contraception, that can be used sporadically or after unprotected intercourse.

This study examines factors associated with the use of biomedical care during pregnancy in Guatemala, focusing on the extent to which complications in an ongoing or previous pregnancy affect a woman's decisions to seek care. The findings, based on multilevel models, suggest that obstetrical need, as well as demographic, social, and cultural factors, are important predictors of pregnancy care. In contrast, measures of availability and access to health services have modest effects. The results also suggest the importance of unobserved variables-such as quality of care-in explaining women's decisions about pregnancy care. These results imply that improving proximity to biomedical services is unlikely to have a dramatic impact on utilization in the absence of additional changes that improve the quality of care or reduce barriers to access. Moreover, current efforts aimed at incorporating midwives into the formal health-care system may need to extend their focus beyond the modification of midwife practices to consider the provision of culturally appropriate, high-quality services by traditional and biomedical providers alike. r

Objectives: To explore three questions: 1) Do chronic stressors predict physiological dysregulation? 2) Is that relationship moderated by characteristics of the individual and his or her social environment? and 3) Do perceived levels of stress mediate the relationship between stressors and dysregulation? Methods: Data come from a nationally representative, longitudinal study of older Taiwanese (n ϭ 916). Regression models are used to examine the relationship between the number of life challenges (i.e., stressors) during 1996 to 2000 and physiological dysregulation (in 2000) based on 16 biomarkers that reflect neuroendocrine function, immune system, cardiovascular function, and metabolic pathways. We include interaction terms to test whether psychosocial vulnerability moderates the impact of stressors. Additional models evaluate the mediating effects of perceived stress. Results: We find a positive association between the number of stressors and physiological dysregulation. The results indicate that this relationship is stronger for persons with greater psychosocial vulnerability, but even so, the magnitude of the effect remains modest. We find some evidence that the level of perceived stress mediates the relationship between chronic stressors and physiological dysregulation. Conclusions: Our results provide some support for the theory of allostatic load, although the relationship between life challenges and physiological dysregulation is weak. The evidence also supports the stress-buffering hypothesis: the combination of low social position, weak social networks, and poor coping ability is associated with greater physiological consequences of life challenges.

No abstract